Several analytical methods in molecular biology (e.g., sequencing library preparation) require that adaptor sequence by placed onto the end of an enriched DNA fragment in order to provide a way to manipulate that fragment. For example, one or more adaptors may be ligated onto an enriched fragment of DNA to produce an adaptor-ligated fragment, and the adaptor-ligated fragment may be amplified and/or sequenced using a primer binding site that are present in the added adaptor.